The present invention relates to adaptive computer peripherals.
Manufacturers of computer peripherals generally produce the same type of peripheral with several different interfaces, so that end users having a computer with only one type of interface may use the peripheral. For example, an external modem may be supplied in two varieties, one having a serial interface, and another a PCMCIA interface. Likewise, a computer mouse might be supplied in two varieties, a parallel mouse and a serial mouse.
Such duplication of products means that manufacturers must often design, manufacture and test a multiplicity of different products. Retailers have a similar problem in that they must supply and stock a large variety of different products. Difficulties arise when a purchaser requests a particular peripheral without specifying the interface with which it is to be used, or alternatively specifies the interface wrongly. In either event, the purchaser receives a product that is incompatible with his own computer system.
The problem of incompatible interfaces on a computer and on a peripheral is of course well known. One approach is to provide additional hardware, either on the computer, on the peripheral, or by way of interchangeable hardware interfaces which sit between the computer and the peripheral. Such approaches are illustrated in U.S. Pat. Nos. 5,280,621, 5,347,113, and 5,258,604. An appropriate interface could be incorporated either within the computer, or within the peripheral, the latter being the approach illustrated in U.S. Pat. No. 5,179,270. An alternative approach is to force both the computer and the peripheral to communicate by means of a common format or protocol. This requires a mechanism for translating the native protocols of both the computer and the peripheral to the common protocol, and vice-versa. Such an approach is used in U.S. Pat. Nos. 4,458,439 and 4,897,799. It is also known to provide hardware or software in the peripheral which allows the peripheral to emulate the communications protocol required by the main computer, as shown in U.S. Pat. No. 5,567,925. Finally, for the sake of completeness, U.S. Pat. No. 4,866,257 may be referred to illustrate the general teaching of a host computer controlling a computer peripheral via an interface within the peripheral.
It is an object of the present invention to enhance the flexibility of computer peripherals by providing a peripheral which is capable of communicating via a number of different protocols, according to instructions received from the computer via a conventional interface.
It is a further object, in at least some embodiments, to provide that flexibility without the need for the computer to include any additional hardware.
According to a first aspect of the present invention there is provided a computer peripheral comprising:
(a) an electrical interface connector for connecting the peripheral for external communication;
(b) a functional module for performing functions of the peripheral; and
(c) an interface adapter, coupled to the electrical interface connector and to the functional module, the interface adapter being configured to select one of a first communications protocol and a second communications protocol, by which selected protocol the peripheral communicates externally via the electrical interface connector, according to one or more external control signals received at the electrical interface connector.
According to a second aspect of the invention there is provided a computer system comprising a computer peripheral as previously defined, in combination with a computer, the electrical interface connector of the peripheral being coupled with a peripheral connector of the computer for communication between the peripheral and the computer.
According to a further aspect of the invention there is provided a method of controlling a computer peripheral having an electrical interface, a functional module for performing functions of the peripheral, and an interface adapter coupled to the electrical interface and to the functional module, the method comprising the steps of:
(a) supplying an external control signal at the electrical interface;
(b) on receipt of the control signal by the interface adapter, selecting a communications protocol by which the peripheral will communicate externally; and
(c) effecting external communications, via the electrical interface, according to the selected protocol.
According to yet a further aspect of the invention there is provided a method of controlling communications within a computer system comprising a coupled computer and computer peripheral, the method comprising the steps of:
(a) causing the computer to send a control signal to the peripheral;
(b) selecting a communications protocol in dependence upon the control signal; and
(c) effecting communication between the computer and the peripheral according to the selected protocol.
In brief, the invention features a computer peripheral that includes a functional module, an electrical interface connector configured to convey one interface set of signals, and an interface adapter that processes signals passing between the electrical interface connector and the functional module and that permits a second interface set of signals to be conveyed via the electrical interface connector.
Embodiments of the invention may include one or more of the following features. The first interface set of signals can be that of a PCMCIA-type set of signals, or a parallel interface-type set of signals. As is known to those skilled in the art, PCMCIA is a standard for connecting peripherals to computers which has been set by the Personal Computer Memory Card International Association.
The standard interface set of signals can be that of a personal computer serial interface, parallel interface, or both. The interface adapter can permit the second interface set of signals to be conveyed via the electrical interface connector upon receipt of an interface change signal conveyed by the electrical interface connector. The interface change signal can include a non-standard signal within the first interface set of signals. Where the first interface protocol is that of a PCMCIA-type set of signals, the interface change signal can include having both output enable (OE) and write enable (WE) low. The electrical interface connector can be a PCMCIA-type connector. An adapter cable having two ends can couple one end to the electrical interface connector associated with the first interface set of signals, and the second end to a second electrical interface connector associated with the second interface set of signals.
The advantages of the invention may include one or more of the following. A single computer peripheral can provide several standard interfaces, including a PCMCIA-compliant interface, a serial port and an microprocessor compatible I/O parallel port. A simple set of signals (Output Enable and Write Enable) tied low can convert the interface module to provide the parallel and serial port options. Only one computer peripheral need be designed, manufactured, maintained, stocked, qualified and sold to provide a variety of standard interfaces to end users. A simple adapter cable can couple the computer peripheral to another type of electrical interface connector, e.g. a peripheral with a PCMCIA-type electrical interface connector can be coupled to a computer with a serial-type electrical interface connector.
Other features and advantages of the invention will become apparent from the following description and from the claims.